In the past, as an amplifying device in which an amplifier is operated in a saturated state, there has been an amplifying device based on an outphasing method (hereinafter, called an “outphasing amplifier”). The outphasing amplifier includes parallel amplifiers and a combiner that combines outputs of the amplifiers and that generates an output signal. The amplifiers amplify respective signals generated by splitting a signal input to the outphasing amplifier. Phase differences between the amplified signals fluctuate in accordance with an absolute value of an amplitude of the input signal.
Here, in the outphasing amplifier, in a case where a signal such as a modulation signal, whose phase and amplitude fluctuate, is input as the input signal, a phase of the input signal is inverted 180 degrees at a point of time when the absolute value of the amplitude of the input signal becomes a minimum. Therefore, in the outphasing amplifier, control is performed in which phases of the signals amplified by the amplifiers are inverted 180 degrees in accordance with the point of time when the absolute value of the amplitude of the input signal becomes a minimum.
A technology of the related art is disclosed in Japanese Laid-open Patent Publication No. 2013-225827.